Newly qualified police officers in Hendon, north London. A survey has found that four in 10 female officers have considered quitting. Photograph: Stefan Rousseau/PA

More than four out of 10 female police officers are so disillusioned with their profession that they have seriously considered quitting, according to a survey of all female members of the force in England and Wales.

The findings prompted demands on Saturday from the former Metropolitan police commissioner Lord Stevens, who is heading an investigation into the future of policing, for ministers to address a "morale crisis" at the heart of the profession.

Stevens said he had decided to release the findings to the Observer before his commission publishes its report next March because they raised such serious questions for the police service.

"These figures are very alarming. It may be that while addressing issues of ethnicity following the Stephen Lawrence case we have taken our eye off the ball on issues of gender," he said.

"We cannot wait any longer. The issues behind the morale crisis need to be addressed as a matter of urgency."

Among the main reasons for low morale that emerged in responses were the lack of opportunities for flexible working and a belief that the force does not take into account women's particular circumstances both when they are pregnant and when they return to work after having a child.

Many women said planned reforms to the service, including changes to police pensions and the increasing involvement of the private sector, added to a sense of uncertainty about their future roles.

The commission, which was established by Labour but is operationally entirely independent, conducted an online survey of the more than 30,000 serving female officers in May.

Out of 3,410 responses – a very high number for such a survey – 42% said they had "given serious thought" to leaving. The proportion saying they were uncertain whether they would stay in the force was consistent across all ranks.

Just 20% said they were happy with the way things were in the force and a full 76% said they were pessimistic about the future of the service as a whole.

Jennifer Brown, a professor of criminology at the London School of Economics who carried out the survey with the help of the Police Federation, which represents rank-and-file officers, said the findings reflected "a deep sense of disquiet" among women who felt they were "not part of the conversation about the new direction they feel is being imposed on their service".

Members of the commission have already taken evidence from expert witnesses including Tom Winsor, the newly appointed chief inspector of constabulary, former home secretaries, police staff associations and thinktanks. Its final report will be published next March.

Commission member Baroness Harris of Richmond, who has worked with the police for 30 years, said the introduction of elected crime commissioners was a real cause of concern within the force, including among female officers.

"Parliament decided that police and crime commissioners were the way forward for ensuring proper police accountability, but we have found little evidence so far that communities share this view. Concerns have been expressed that policing will be politicised and that the role of a PCC was not clear vis-a-vis the position of an area's chief constable.

"There were also concerns around equality in the choice of a police and crime commissioner and whether or not pandering to popular policies would detract from the less visible, but potentially much more serious 'silent crimes' such as domestic violence."

She said it was vital that women were encouraged to stay in the force because they often made "brilliant" officers and in many cases were more effective at dealing with disorder than men. "I have witnessed cases of disorder where women officers have walked into difficult sometimes violent situations and calmed things down immediately. They want to serve and we must find ways to keep them."

Harris said the unhappiness of women officers was not the result of sexism within the force so much as feeling that their particular demands were not recognised or considered often enough.

One officer with 22 years of service remarked: "Morale is the lowest I have ever known. The changes in our force are ill conceived. I have worked in CID for over 15 years but due to lack of frontline recruitment we are having to backfill any uniform vacancies. Do I feel my experience is valued? Absolutely not! I wish I could leave tomorrow."